A device for adjusting the height of the semitrailer support device for a semitrailer tractor is known from European Patent specification 0 576 722 B1. Said device makes it possible to use the semitrailer tractor with semitrailers of different heights. For this purpose, a support plate for attachment of a fifth wheel is mounted above a base plate. The supporting plate can be lifted by a lifting device. In the lifted condition, the support plate can be supported by pivot members which are pivotably connected to the base plate and can be pivoted upwardly.
This device allows only two different height adjustment positions of the fifth wheel.
It is an object of the invention to provide a semitrailer support device which, while being of a simple construction, allows for a large number of different height adjustment positions of the fifth wheel.